GAS GENERANT COMPOSITION, PREPARATION METHOD THEREFOR, AND USE THEREOF

Abstract

Provided are a gas generant composition, a preparation method, and a gas generator containing the composition. The gas generant composition includes components having the following contents, in percent by mass: 40% to 60% of guanidine nitrate, 25% to 50% of basic copper nitrate, 0% to 7% of ammonium perchlorate, 1% to 10% of a slag-forming agent, and 0.05% to 5% of a release agent/lubricant, the slag-forming agent is used as a form-retaining agent, so that the tablets can retain their form before combustion very well after combustion, thereby completely avoiding burning of an inflatable bag due to melting and splashing of the combusted tablets. Moreover, ammonium perchlorate is used as auxiliary oxidizers, thereby reducing the amount of basic cupric nitrate used and reducing molten copper residues. The gas generant composition is mainly used in a gas generator for vehicle airbag.

Claims

1. A gas generant composition, comprising guanidine nitrate, basic copper nitrate and ammonium perchlorate, further comprising a slag-forming agent and a lubricant, wherein the slag-forming agent is at least one zirconate, at least one silicate or a mixture of at least one zirconate and at least one silicate, wherein contents, in percent by mass, of respective components are as follows: TABLE-US-00012 guanidine nitrate 40% to 60%; basic copper nitrate 25% to 50%; ammonium perchlorate 0% to 7%; slag-forming agent  1% to 10%; and lubricant 0.05% to 5%.  

2. The gas generant composition according to claim 1, wherein the zirconate is one of strontium zirconate, barium zirconate and calcium zirconate, or a combination therefrom.

3. The gas generant composition according to claim 1, wherein the silicate is one of zirconium silicate and calcium silicate, or a combination therefrom.

4. The gas generant composition according to claim 1, wherein the slag-forming agent is the mixture of at least one zirconate and at least one silicate, in which a mass ratio of zirconate to silicate is 1:0.5-3.

5. The gas generant composition according to claim 4, wherein the slag-forming agent is a mixture of strontium zirconate, zirconium silicate and calcium silicate in a mass ratio of 1:0.2-1.5:0.3-1.5.

6. The gas generant composition according to claim 1, wherein the slag-forming agent is a mixture of strontium zirconate and barium zirconate in a mass ratio of 1:0.5-3.

7. The gas generant composition according to claim 1, wherein the lubricant is one of talc, graphite, calcium stearate, magnesium stearate, molybdenum disulfide and boron nitride, or a combination therefrom.

8. The gas generant composition according to claim 1, wherein the ammonium perchlorate has a particle size D90 not greater than 20 μm; and the slag-forming agent has a particle size D90 not greater than 5 μm.

9. The gas generant composition according to claim 1, wherein the basic copper nitrate and the lubricant each have a particle size D90 not greater than 5 μm.

10. The gas generant composition according to claim 1, wherein a sum of water contents in the respective components of the gas generant composition is not more than 1 of a total mass of the respective components.

11. The gas generant composition according to claim 1, wherein the gas generant composition is molded as a circular or elliptical sheet structure, a circular or elliptical columnar structure, a special-shaped sheet or columnar structure, a circular or elliptical monoporous structure, a circular or elliptical porous structure, or a special-shaped monoporous or porous structure.

12. The gas generant composition according to claim 11, wherein the circular sheet structure has a diameter of 3 to 15 mm and a height of 2 to 5 mm; the circular columnar structure has a diameter of 3 to 15 mm and a height of 5 to 15 mm; the circular monoporous structure has an inner diameter of 0.5 to 2.5 mm, an outer diameter of 3 to 15 mm and a height of 3 to 15 mm; and the elliptical monoporous structure has an inner diameter of 0.5 to 2.5 mm, a major diameter of 3 to 20 mm, a minor diameter of 2 to 12 mm and a height of 3 to 15 mm.

13. A method for preparing the gas generant composition according to claim 1, wherein the gas generant composition is prepared by wet granulation, spray granulation or dry granulation, wherein a preparation method for the wet granulation comprises steps of: (1) mixing guanidine nitrate, basic copper nitrate, ammonium perchlorate and the slag-forming agent to obtain a first material; (2) performing wet mixing on the first material by adding water, to obtain a second material, wherein an amount of water added is 5% to 15% of a total mass of the first material; (3) making the second material pass through a sieve of 10 to 40 meshes to obtain a third material; (4) drying the third material to a water content less than 0.5% of a total mass of the third material, and making the third material pass through a sieve of 10 to 40 meshes again to obtain a fourth material; and (5) adding a lubricant to the fourth material and molding the material.

14. The method for preparing the gas generant composition according to claim 13, wherein in the step (1), the first material is obtained by mixing guanidine nitrate, basic copper nitrate, ammonium perchlorate and the slag-forming agent in a mixing device for a mixing duration larger than or equal to 5 min.

15. The method for preparing the gas generant composition according to claim 13, wherein the wet mixing in the step (2) is performed for a duration of 20 min to 60 min; and the wet mixing is performed by a device selected from a kneader and a mixer.

16. A method for preparing the gas generant composition according to claim 1, wherein the gas generant composition is prepared by wet granulation, and a preparation method comprises steps of: (1) mixing guanidine nitrate, basic copper nitrate, ammonium perchlorate, the slag-forming agent and the lubricant to obtain a first material; (2) performing wet mixing on the first material by adding water, to obtain a second material, wherein an amount of water added is 5% to 15% of a total mass of the first material; (3) making the second material pass through a sieve of 10 to 40 meshes to obtain a third material; (4) drying the third material to a water content less than 0.5% of a total mass of the third material, and making the third material pass through a sieve of 10 to 40 meshes again to obtain a fourth material; and (5) molding the fourth material.

17. The method for preparing the gas generant composition according to claim 16, wherein in the step (1), the first material is obtained by mixing guanidine nitrate, basic copper nitrate, ammonium perchlorate, the slag-forming agent and the lubricant in a mixing device for a mixing duration larger than or equal to 5 min.

18. The method for preparing the gas generant composition according to claim 16, wherein the wet mixing in the step (2) is performed for a duration of 20 min to 60 min; and the wet mixing is performed by a device selected from a kneader and a mixer.

19. The gas generant composition according to claim 1, wherein the zirconate is barium zirconate.

20. The gas generant composition according to claim 1, wherein the basic copper nitrate has a specific surface area of 1.0-8.0 m.sup.2/g.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0073] FIG. 1 is a picture showing the morphology of residues obtained after combustion of gas generant composition tablets in Comparative Example 1 of the present disclosure;

[0074] FIG. 2 is a picture showing the morphology of residues obtained after combustion of gas generant composition tablets in Example 1 of the present disclosure;

[0075] FIG. 3 is a picture showing the morphology of residues obtained after combustion of gas generant composition tablets in Comparative Example 2 of the present disclosure;

[0076] FIG. 4 is a picture showing the morphology of residues obtained after combustion of gas generant composition tablets in Example 2 of the present disclosure;

[0077] FIG. 5 is a picture showing the morphology of residues obtained after combustion of gas generant composition tablets in Comparative Example 3 of the present disclosure;

[0078] FIG. 6 is a picture showing the morphology of residues obtained after combustion of gas generant composition tablets in Example 3 of the present disclosure;

[0079] FIG. 7 is a picture showing the morphology of residues obtained after combustion of gas generant composition tablets in Example 4 of the present disclosure;

[0080] FIG. 8 is a picture showing the morphology of residues obtained after combustion of gas generant composition tablets in Example 5 of the present disclosure;

[0081] FIG. 9 is a picture showing the morphology of residues obtained after combustion of gas generant composition tablets in Example 6 of the present disclosure;

[0082] FIG. 10 is a picture showing the morphology of residues obtained after combustion of gas generant composition tablets in Example III of the present disclosure; and

[0083] FIG. 11 is a picture showing the morphology of residues obtained after combustion of gas generant composition tablets in Example IV of the present disclosure

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0084] The present disclosure will be described in further detail below with reference to the accompanying drawings and specific examples.

[0085] Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. The word “about,” when accompanying a numerical value, is to be construed as indicating a deviation of up to and inclusive of 10% from the stated numerical value. The use of any and all examples, or exemplary language (“e.g.” or “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any nonclaimed element as essential to the practice of the invention.

[0086] The present disclosure discloses a gas generant composition, comprising guanidine nitrate, basic copper nitrate, strontium nitrate, ammonium perchlorate, a slag-forming agent, and a lubricant, wherein the slag-forming agent is at least one zirconate, or at least one silicate, or a mixture of at least one zirconate and at least one silicate, and the lubricant is selected from at least one of talc, graphite, calcium stearate, magnesium stearate, molybdenum disulfide, or boron nitride.

[0087] The contents, in percent by mass, of the respective components are as follows: guanidine nitrate at about 40% to 55%; basic copper nitrate at about 25% to 45%; strontium nitrate at about 1% to 8%; ammonium perchlorate at about 1% to 7%; slag-forming agent at about 1% to 10%; lubricant at about 0.5% to 5%.

[0088] The above-mentioned zirconate is one or a combination of strontium zirconate, barium zirconate, or calcium zirconate.

[0089] The above-mentioned silicate is one or a combination of zirconium silicate or calcium silicate.

[0090] The above-mentioned slag-forming agent is a mixture of at least one zirconate and at least one silicate, in which the mass ratio of zirconate to silicate is 1:0.5-3.

[0091] In an optional embodiment of the present disclosure, the slag-forming agent is a mixture of strontium zirconate, zirconium silicate, and calcium silicate in a mass ratio of 1:0.5-3:0.5-3.

[0092] In an optional embodiment of the present disclosure, the slag-forming agent is a mixture of strontium zirconate and barium zirconate in a mass ratio of 1:0.5-3.

[0093] The above-mentioned ammonium perchlorate has a particle size D90 not greater than 20 μm.

[0094] The above-mentioned slag-forming agent has a particle size D90 not greater than 5 μm.

[0095] The above-mentioned basic copper nitrate and the lubricant/release agent each have a particle size D90 not greater than 5 μm.

[0096] A sum of water contents in the respective components of the gas generant composition described above is not more than 1% of the total mass of the respective components.

[0097] In an optional embodiment of the present disclosure, the gas generant composition is molded as a circular or elliptical sheet structure, a circular or elliptical columnar (or cylindrical) structure, a special-shaped sheet or columnar structure, a circular or elliptical monoporous structure, a circular or elliptical porous structure, or a special-shaped monoporous or porous structure. Here, the circular sheet structure has a diameter of 3 to 15 mm and a height of 2 to 5 mm; the circular columnar structure has a diameter of 3 to 15 mm and a height of 5 to 15 mm; the circular monoporous structure has an inner diameter of 0.5 to 2.5 mm, an outer diameter of 3 to 15 mm, and a height of 3 to 15 mm; and the elliptical monoporous structure has an inner diameter of 0.5 to 2.5 mm, a major diameter of 3 to 20 mm, a minor diameter of 2 to 12 mm, and a height of 3 to 15 mm.

[0098] A method for preparing a gas generant composition according to the present disclosure may be carried out by a method comprising wet granulation, spray granulation, or dry granulation. Here, spray granulation or dry granulation may be carried out by using a traditional granulation process method.

[0099] Here, a specific preparation method for wet granulation includes the following steps.

[0100] (1) Guanidine nitrate, basic copper nitrate, strontium nitrate, ammonium perchlorate, and a slag-forming agent are mixed to obtain a first material, where they are mixed in a mixing device for a mixing duration larger than or equal to 5 min. The mixing device may be a pneumatic mixer, a V-type mixer, a three-dimensional multi-directional motion mixer, an automatic lifting hopper mixer, a vibration mill, a ribbon mixer, or an acoustic resonance mixer.

[0101] (2) The first material is subjected to wet mixing with addition of water to obtain a second material, where the wet mixing is performed for a duration of 20 min to 60 min, wherein the amount of water added is 5% to 15% of the total mass of the first material, and distilled water is preferably added. The device for wet mixing is a kneader or a mixer and may, for example, be selected from a horizontal kneader, a vertical kneader, a ribbon mixer, or an acoustic resonance mixer.

[0102] (3) The second material is caused to pass through a sieve having 10 to 40 meshes to obtain a third material.

[0103] (4) The third material is dried to a water content less than 0.5% of the total mass of the third material and is caused to pass through the sieve (screen) having 10 to 40 meshes again to obtain a fourth material. The drying device may be an electric heating oven, an oil bath oven, a steam oven, a double-cone oven, a vibrating fluidized bed, or a belt vacuum dryer.

[0104] (5) A lubricant is added to the fourth material and the material is molded. The molding device may be a hydraulic press, a rotary tablet press, or a powder molding machine. It may be molded as a circular or elliptical sheet structure, a circular or elliptical columnar structure, a special-shaped sheet or columnar structure, a circular or elliptical monoporous structure, a circular or elliptical porous structure, or a special-shaped monoporous or porous structure. In an optional embodiment of the present disclosure, the circular sheet structure has a diameter of 3 to 15 mm and a height of 2 to 5 mm; the circular columnar structure has a diameter of 3 to 15 mm and a height of 5 to 15 mm; the circular monoporous structure has an inner diameter of 0.5 to 2.5 mm, an outer diameter of 3 to 15 mm, and a height of 3 to 15 mm; and the elliptical monoporous structure has an inner diameter of 0.5 to 2.5 mm, a major diameter of 3 to 20 mm, a minor diameter of 2 to 12 mm, and a height of 3 to 15 mm.

[0105] Another specific preparation method for wet granulation includes the following steps.

[0106] (1) Guanidine nitrate, basic copper nitrate, strontium nitrate, ammonium perchlorate, a slag-forming agent, and a lubricant are mixed to obtain a first material, where they are mixed in a mixing device for a mixing duration larger than or equal to 5 min. The mixing device may be a V-type mixer, a three-dimensional multi-directional motion mixer, an automatic lifting hopper mixer, a vibration mill, a ribbon mixer, or an acoustic resonance mixer.

[0107] (2) The first material is subjected to wet mixing with addition of water to obtain a second material, where the wet mixing is performed for a duration of 20 min to 60 min, wherein the amount of water added is 5% to 15% of the total mass of the first material, and distilled water is preferably added. The device for wet mixing is a kneader or a mixer and may, for example, be selected from a horizontal kneader, a vertical kneader, a ribbon mixer, or an acoustic resonance mixer.

[0108] (3) The second material is caused to pass through a sieve having 10 to 40 meshes to obtain a third material.

[0109] (4) The third material is dried to a water content less than 0.5% of the total mass of the third material and is caused to pass through the sieve having 10 to 40 meshes again to obtain a fourth material. The drying device may be an electric heating oven, an oil bath oven, a steam oven, a double-cone oven, a vibrating fluidized bed, or a belt vacuum dryer.

[0110] (5) The fourth material is molded. The molding device may be a hydraulic press, a rotary tablet press, or a powder molding machine.

[0111] The above-mentioned gas generant composition of the present disclosure is used in a gas generator of a vehicle airbag.

[0112] In the gas generant formulation based on basic copper nitrate and guanidine nitrate according to the present disclosure, zirconate, silicate, or a mixture of zirconate and silicate is added for the first time as a slag-forming agent of the gas generant, so that molten copper metal can be coagulated and agglomerated into lumps. The slag-forming agent has a melting point about 2,500 K, which is much higher than the melting point of metallic copper. A large number of tests have shown that the slag-forming agent is less combustible and can gather all the solid combustion products and agglomerates together during combustion of the gas generant composition, so that the gas generant retains its original shape after being combusted. Zirconate, silicate, or a mixture thereof used in the present disclosure can create a good effect of coagulating a metallic copper melt formed after the decomposition of basic copper nitrate, to further reduce molten copper residues, and can serve to increase the viscosity of the molten residues and to maintain its own shape as a tablet matrix, thereby obtaining significant agglomeration and slagging effects.

[0113] In the following examples, the mixing device used is a three-dimensional multi-directional motion mixer (or an ultra-efficient mixer), the kneader used is a horizontal kneader, the drying device used is a vacuum oven, and the molding device used is a rotary tablet press.

Comparative Example 1

[0114] A gas generant composition comprised components having the following contents, in percent by mass: guanidine nitrate at about 40%; basic copper nitrate at about 40%; strontium nitrate at about 12.75%; ammonium perchlorate at about 1%; strontium titanate at about 5.5%; talc at about 0.75%.

[0115] These components were weighed and then were pressed into round tablets with a diameter of 5 mm and a thickness of 1.9 mm by wet granulation and by a rotary tablet press. The specific preparation method was carried out as follows. Guanidine nitrate, basic copper nitrate, strontium nitrate, ammonium perchlorate, and strontium titanate were mixed by a mixing device to obtain a first material; 15% of distilled water was added to the first material and the first material was subjected to wet kneading for 60 min to obtain a second material, and the second material was caused to pass through a 40-mesh sieve to obtain a third material; the third material was dried to a water content less than 0.5% of the total mass of the third material and was caused to pass through the 40-mesh sieve again to obtain a fourth material; talc was added to the fourth material, and the material was molded by a rotary tablet press.

[0116] The prepared round tablets were loaded into a test generator and subjected to an ignition and combustion test. After the test, the generator was dissected to observe the form of the combusted tablets.

[0117] FIG. 1 was a picture showing the morphology of residues obtained after combustion of the gas generant composition tablets in Comparative Example 1 of the present disclosure. Table 1 below showed statistics of the weights of soluble residues and insoluble residues discharged after the combustion of the gas generant composition tablets in Comparative Example 1 of the present disclosure and their low-temperature ignition delay time. It could be seen from FIG. 1 and Table 1 that the tablets were in the form of sheets, were tightly attached to the inner wall of the filter, had poor density, were easily broken when touched by hand, and would tend to fly out of the generator filter and fall into the airbag and might burn through the inflatable bag and cause potential danger to a human body. Their low-temperature ignition time met the requirement of being less than 7 ms.

TABLE-US-00001 TABLE 1 Water-soluble Insoluble Total Ignition PH Matter Matter Weight Delay No. Value Weight (g) Weight (g) (g) Time (ms) 001 5.89 0.602 0.026 0.628 3.9 002 5.52 0.459 0.029 0.488 4.5 003 5.50 0.502 0.015 0.517 4.1 AVE 5.64 0.521 0.023 0.544 4.3

Example 1

[0118] A gas generant composition comprised components having the following contents, in percent by mass: guanidine nitrate at about 40%; basic copper nitrate at about 42.75%; strontium nitrate at about 8%; ammonium perchlorate at about 3%; barium zirconate at about 5.5%; talc at about 0.75%.

[0119] These components were weighed and then were pressed into round tablets with a diameter of 5 mm and a thickness of 1.9 mm by wet granulation and by a rotary tablet press. The specific preparation method was carried out as follows. Guanidine nitrate, basic copper nitrate, strontium nitrate, ammonium perchlorate, and barium zirconate were mixed by a mixing device to obtain a first material; 15% of distilled water was added to the first material and the first material was subjected to wet kneading for 60 min to obtain a second material, and the second material was caused to pass through a 40-mesh sieve to obtain a third material; the third material was dried to a water content less than 0.5% of the total mass of the third material and was caused to pass through the 40-mesh sieve again to obtain a fourth material; talc was added to the fourth material, and the material was molded by a rotary tablet press.

[0120] The prepared round tablets were loaded into a test generator and subjected to an ignition and combustion test. After the test, the generator was dissected to observe the form of the combusted tablets.

[0121] FIG. 2 was a picture showing the morphology of residues obtained after combustion of the gas generant composition tablets in Example 1 of the present disclosure. Table 2 below showed statistics of the weights of soluble residues and insoluble residues discharged after the combustion of the gas generant composition tablets in Example 1 of the present disclosure and their low-temperature ignition delay time. It could be seen from FIG. 2 and Table 2 that after combusted at high temperature, the tablets were in the form of the original tablet, were tightly attached to the inner wall of the filter, and had larger density. The tablets had retained a very good original appearance and had higher strength and higher density to support the maintaining of their original appearance. Their low-temperature ignition time met the requirement of being less than 7 ms.

TABLE-US-00002 TABLE 2 Water-soluble Insoluble Total Ignition PH Matter Matter Weight Delay No. Value Weight (g) Weight (g) (g) Time (ms) 1 5.42 0.342 0.019 0.361 3.2 2 5.23 0.323 0.011 0.334 3.1 3 5.64 0.31 0.009 0.319 3.1 AVE 5.43 0.325 0.013 0.338 3.1

[0122] In this example, barium zirconate was added as a slag-forming agent, basic copper nitrate was used as a primary oxidizer, guanidine nitrate was used as a fuel, AP and strontium nitrate were used as auxiliary oxidizers, and talc was used as a lubricant and a release agent. The tablets retained a very good original appearance after being tested in a generator for an airbag. After a TANKWASH test was conducted, the weight of the water-soluble matter and the weight of the insoluble matter were decreased significantly. Moreover, the composition was combusted at an increased speed and had an ignition delay that met the strict requirements of USCAR.

Comparative Example 2

[0123] A gas generant composition comprised components having the following contents, in percent by mass: guanidine nitrate at about 52%; at about basic copper nitrate 44%; strontium titanate at about 4%.

[0124] These components were weighed and then were pressed into round tablets with a diameter of 5 mm and a thickness of 1.9 mm by wet granulation and by a rotary tablet press. The specific preparation method was carried out as follows. Guanidine nitrate, basic copper nitrate, and strontium titanate were mixed by a mixing device to obtain a first material; 10% of distilled water was added to the first material and the first material was subjected to wet kneading for 50 min to obtain a second material, and the second material was caused to pass through a 35-mesh sieve to obtain a third material; the third material was dried to a water content less than 0.5% of the total mass of the third material and was caused to pass through the 35-mesh sieve again to obtain a fourth material; and talc was added to the fourth material, and the material was molded (shaped) by a rotary tablet press.

[0125] The prepared round tablets were loaded into a test generator and subjected to an ignition and combustion test. After the test, the generator was dissected to observe the form of the combusted tablets.

[0126] FIG. 3 was a picture showing the morphology of residues obtained after combustion of the gas generant composition tablets in Comparative Example 2 of the present disclosure. Table 3 below showed statistics of the weights of soluble residues and insoluble residues discharged after the combustion of the gas generant composition tablets in Comparative Example 2 of the present disclosure and their low-temperature ignition delay time. It could be seen from FIG. 3 and Table 3 that the tablets were in the form of sheets and partially in powder form, were tightly attached to the inner wall of the filter, had poor density, and would tend to fly out of the generator filter and fall into the airbag and might burn through the inflatable bag and cause potential danger to a human body. Their low-temperature ignition time did not meet the requirement of being less than 7 ms.

TABLE-US-00003 TABLE 3 Water-soluble Insoluble Ignition PH Matter Matter Total Delay No. Value Weight (g) Weight (g) Weight (g) Time (ms) 1 5.78 1.012 0.159 1.171 11.2 2 5.71 0.997 0.186 1.183 15.4 3 5.68 1.022 0.199 1.221 16.5 AVE 5.72 1.010 0.181 1.192 14.4

Example 2

[0127] A gas generant composition comprised components having the following contents, in percent by mass: guanidine nitrate at about 50%; basic copper nitrate at about 41.5%; strontium nitrate at about 1.5%; ammonium perchlorate at about 2%; strontium zirconate at about 4%; talc 1%.

[0128] These components were weighed and then were pressed into round tablets with a diameter of 5 mm and a thickness of 1.9 mm by wet granulation and by a rotary tablet press. The specific preparation method was carried out as follows. Guanidine nitrate, basic copper nitrate, strontium nitrate, ammonium perchlorate, strontium zirconate, and talc were mixed by a mixing device to obtain a first material; 10% of distilled water was added to the first material and the first material was subjected to wet kneading for 50 min to obtain a second material, and the second material was caused to pass through a 35-mesh sieve to obtain a third material; the third material was dried to a water content less than 0.5% of the total mass of the third material and was caused to pass through the 35-mesh sieve again to obtain a fourth material; talc was added to the fourth material, and the material was molded by a rotary tablet press.

[0129] The prepared round tablets were loaded into a test generator and subjected to an ignition and combustion test. After the test, the generator was dissected to observe the form of the combusted tablets.

[0130] FIG. 4 was a picture showing the morphology of residues obtained after combustion of the gas generant composition tablets in Example 2 of the present disclosure. Table 4 below showed statistics of the weights of soluble residues and insoluble residues discharged after the combustion of the gas generant composition tablets in Example 2 of the present disclosure and their low-temperature ignition delay time. It could be seen from FIG. 4 and Table 4 that after combusted at high temperature, the tablets were in the form of the original tablet and exhibited a significant coagulation effect. The residues were tightly attached to the inner wall of the filter and had larger density. The tablets had retained a very good original appearance and had higher strength and higher density to support the maintaining of their original appearance. Their low-temperature ignition time met the requirement of being less than 7 ms.

TABLE-US-00004 TABLE 4 Water-soluble Insoluble Total Ignition PH Matter Matter Weight Delay No. Value Weigh (g) Weight (g) (g) Time (ms) 1 5.12 0.321 0.012 0.333 2.8 2 5.34 0.213 0.008 0.221 2.7 3 5.48 0.216 0.018 0.234 2.5 AVE 5.31 0.250 0.013 0.263 2.7

[0131] In this example, strontium zirconate was added as a slag-forming agent, basic copper nitrate was used as a primary oxidizer, guanidine nitrate was used as a fuel, AP and strontium nitrate were used as auxiliary oxidizers, and talc was used as a lubricant and a release agent. The tablets retained a very good original appearance after being tested in a generator for an airbag. After a TANKWASH test was conducted, the weight of the water-soluble matter and the weight of the insoluble matter were decreased significantly. Moreover, the composition was combusted at an increased speed and had an ignition delay that met the strict requirements of USCAR.

Comparative Example 3

[0132] A gas generant composition comprised components having the following contents, in percent by mass: guanidine nitrate at about 45%; basic copper nitrate at about 40%; potassium perchlorate at about 5%; copper oxide at about 4%; silicon dioxide at about 5%; calcium stearate at about 1%.

[0133] These components were weighed and then were pressed into round tablets with a diameter of 5 mm and a thickness of 1.9 mm by wet granulation and by a rotary tablet press. The specific preparation method was carried out as follows. Guanidine nitrate, basic copper nitrate, copper oxide, potassium perchlorate, silicon dioxide, and calcium stearate were mixed by a mixing device to obtain a first material; 10% of distilled water was added to the first material and the first material was subjected to wet kneading for 50 min to obtain a second material, and the second material was caused to pass through a 30-mesh sieve to obtain a third material; the third material was dried to a water content less than 0.5% of the total mass of the third material and was caused to pass through the 30-mesh sieve again to obtain a fourth material; talc was added to the fourth material, and the material was molded by a rotary tablet press.

[0134] The prepared round tablets were loaded into a test generator and subjected to an ignition and combustion test. After the test, the generator was dissected to observe the form of the combusted tablets.

[0135] FIG. 5 was a picture showing the morphology of residues obtained after combustion of the gas generant composition tablets in Comparative Example 3 of the present disclosure. Table 5 below showed statistics of the weights of soluble residues and insoluble residues discharged after the combustion of the gas generant composition tablets in Comparative Example 3 of the present disclosure and their low-temperature ignition delay time. It could be seen from FIG. 5 and Table 5 that the tablets were agglomerated after combustion, and a large amount of metallic copper was separated out and attached to the inner wall of the filter but was not agglomerated into a desired sheet shape. As a result, the residue would tend to fly out of the generator filter and fall into the airbag and might burn through the inflatable bag and cause potential danger to a human body. Their low-temperature ignition time met the requirement of being less than 7 ms.

TABLE-US-00005 TABLE 5 Water-soluble Insoluble Total Ignition PH Matter Matter Weight Delay No. Value Weight (g) Weight (g) (g) Time (ms) 1 6.02 1.044 0.238 1.282 4.5 2 5.98 1.12 0.356 1.476 2.3 3 6.12 1.009 0.297 1.306 2.8 AVE 6.04 1.058 0.297 1.355 3.2

Example 3

[0136] A gas generant composition comprised components having the following contents, in percent by mass: guanidine nitrate at about 45%; basic copper nitrate at about 40%; strontium nitrate at about 4%; ammonium perchlorate at about 5%; calcium zirconate at about 5%; calcium stearate at about 1%

[0137] These components were weighed and then were pressed into round tablets with a diameter of 5 mm and a thickness of 1.9 mm by wet granulation and by a rotary tablet press. The specific preparation method was carried out as follows. Guanidine nitrate, basic copper nitrate, strontium nitrate, ammonium perchlorate, calcium zirconate, and calcium stearate were mixed by a mixing device to obtain a first material; 10% of distilled water was added to the first material and the first material was subjected to wet kneading for 50 min to obtain a second material, and the second material was caused to pass through a 30-mesh sieve to obtain a third material; the third material was dried to a water content less than 0.5% of the total mass of the third material and was caused to pass through the 30-mesh sieve again to obtain a fourth material; talc was added to the fourth material, and the material was molded by a rotary tablet press.

[0138] The prepared round tablets were loaded into a test generator and subjected to an ignition and combustion test. After the test, the generator was dissected to observe the form of the combusted tablets.

[0139] FIG. 6 was a picture showing the morphology of residues obtained after combustion of the gas generant composition tablets in Example 3 of the present disclosure. Table 6 below showed statistics of the weights of soluble residues and insoluble residues discharged after the combustion of the gas generant composition tablets in Example 3 of the present disclosure and their low-temperature ignition delay time. It could be seen from FIG. 6 and Table 6 that after combusted at high temperature, the tablets were in the form of the original tablet and exhibited a significant coagulation effect. The residues were tightly attached to the inner wall of the filter and had larger density. The tablets had retained a very good original appearance and had higher strength and higher density to support the maintaining of their original appearance. Their low-temperature ignition time met the requirement of being less than 7 ms.

TABLE-US-00006 TABLE 6 Water-soluble Insoluble Total Ignition PH Matter Matter Weight Delay No. Value Weight (g) Weight (g) (g) Time (ms) 1 5.56 0.329 0.009 0.338 2.8 2 5.59 0.312 0.012 0.324 3.0 3 5.68 0.212 0.023 0.235 2.9 AVE 5.61 0.284 0.015 0.299 2.9

[0140] In this example, calcium zirconate was added as a slag-forming agent, basic copper nitrate was used as a primary oxidizer, guanidine nitrate was used as a fuel, AP and strontium nitrate were used as auxiliary oxidizers, and calcium stearate was used as a lubricant and a release agent. The tablets retained a very good original appearance after being tested in a generator for an airbag. After a TANKWASH test was conducted, the weight of the water-soluble matter and the weight of the insoluble matter were decreased significantly. Moreover, the composition was combusted at an increased speed and had an ignition delay that met the strict requirements of USCAR.

Example 4

[0141] A gas generant composition comprised components having the following contents, in percent by mass: guanidine nitrate at about 51.5%; basic copper nitrate at about 35%; strontium nitrate at about 6%; ammonium perchlorate at about 3%; strontium zirconate at about 2%; barium zirconate at about 2%; magnesium stearate at about 0.5%.

[0142] These components were weighed and then were pressed into round tablets with a diameter of 5 mm and a thickness of 1.9 mm by wet granulation and by a rotary tablet press. The specific preparation method was carried out as follows. Guanidine nitrate, basic copper nitrate, strontium nitrate, ammonium perchlorate, strontium zirconate, barium zirconate, and magnesium stearate were mixed by a mixing device to obtain a first material; 10% of distilled water was added to the first material and the first material was subjected to wet kneading for 60 min to obtain a second material, and the second material was caused to pass through a 40-mesh sieve to obtain a third material; the third material was dried to a water content less than 0.5% of the total mass of the third material and was caused to pass through the 40-mesh sieve again to obtain a fourth material; talc was added to the fourth material, and the material was molded by a rotary tablet press.

[0143] The prepared round tablets were loaded into a test generator and subjected to an ignition and combustion test. After the test, the generator was dissected to observe the form of the combusted tablets.

[0144] FIG. 7 was a picture showing the morphology of residues obtained after combustion of the gas generant composition tablets in Example 4 of the present disclosure. Table 7 below showed statistics of the weights of soluble residues and insoluble residues discharged after the combustion of the gas generant composition tablets in Example 4 of the present disclosure and their low-temperature ignition delay time. It could be seen from FIG. 7 and Table 7 that after combusted at high temperature, the tablets were in the form of the original tablet and exhibited a significant coagulation effect. The residues were tightly attached to the inner wall of the filter and had larger density. The tablets had retained a very good original appearance and had higher strength and higher density to support the maintaining of their original appearance. Their low-temperature ignition time met the requirement of being less than 7 ms.

TABLE-US-00007 TABLE 7 Water-soluble Insoluble Total Ignition PH Matter Matter Weight Delay No. Value Weight (g) Weight (g) (g) Time (ms) 1 6.12 0.422 0.017 0.439 3.2 2 5.81 0.313 0.017 0.33 2.9 3 5.83 0.298 0.029 0.327 2.9 AVE 5.92 0.344 0.021 0.365 3.0

[0145] In this example, strontium zirconate and barium zirconate were added as a slag-forming agent, basic copper nitrate was used as a primary oxidizer, guanidine nitrate was used as a fuel, AP and strontium nitrate were used as auxiliary oxidizers, and magnesium stearate was used as a lubricant and a release agent. The tablets retained a very good original appearance after being tested in a generator for an airbag. After a TANKWASH test was conducted, the weight of the water-soluble matter and the weight of the insoluble matter were decreased significantly. Moreover, the composition was combusted at an increased speed and had an ignition delay that met the strict requirements of USCAR.

Example 5

[0146] A gas generant composition comprised components having the following contents, in percent by mass: guanidine nitrate at about 55%; basic copper nitrate at about 28%; strontium nitrate at about 4%; ammonium perchlorate at about 7%; zirconium silicate at about 4%; talc 2%.

[0147] These components were weighed and then were pressed into round tablets with a diameter of 5 mm and a thickness of 1.9 mm by wet granulation and by a rotary tablet press. The specific preparation method was carried out as follows. Guanidine nitrate, basic copper nitrate, strontium nitrate, ammonium perchlorate, zirconium silicate, and talc were mixed by a mixing device to obtain a first material; 10% of distilled water was added to the first material and the first material was subjected to wet kneading for 55 min to obtain a second material, and the second material was caused to pass through a 35-mesh sieve to obtain a third material; the third material was dried to a water content less than 0.5% of the total mass of the third material and was caused to pass through the 35-mesh sieve again to obtain a fourth material; talc was added to the fourth material, and the material was molded by a rotary tablet press.

[0148] The prepared round tablets were loaded into a test generator and subjected to an ignition and combustion test. After the test, the generator was dissected to observe the form of the combusted tablets.

[0149] FIG. 8 was a picture showing the morphology of residues obtained after combustion of the gas generant composition tablets in Example 5 of the present disclosure. Table 8 below showed statistics of the weights of soluble residues and insoluble residues discharged after the combustion of the gas generant composition tablets in Example 5 of the present disclosure and their low-temperature ignition delay time. It could be seen from FIG. 8 and Table 8 that after combusted at high temperature, the tablets were in the form of the original tablet and exhibited a significant coagulation effect. The residues were tightly attached to the inner wall of the filter and had larger density. The tablets had retained a very good original appearance and had higher strength and higher density to support the maintaining of their original appearance. Their low-temperature ignition time met the requirement of being less than 7 ms.

TABLE-US-00008 TABLE 8 Water-soluble Insoluble Total Ignition PH Matter Matter Weight Delay No. Value Weight (g) Weight (g) (g) Time (ms) 1 5.91 0.391 0.119 0.51 3.3 2 5.89 0.387 0.092 0.479 3.0 3 5.93 0.299 0.078 0.377 3.0 AVE 5.91 0.359 0.096 0.455 3.1

[0150] In this example, zirconium silicate was added as a slag-forming agent, basic copper nitrate was used as a primary oxidizer, guanidine nitrate was used as a fuel, AP and strontium nitrate were used as auxiliary oxidizers, and talc was used as a lubricant and a release agent. The tablets retained a very good original appearance after being tested in a generator for an airbag. After a TANKWASH test was conducted, the weight of the water-soluble matter and the weight of the insoluble matter were decreased significantly. Moreover, the composition was combusted at an increased speed and had an ignition delay that met the strict requirements of USCAR.

Example 6

[0151] A gas generant composition comprised components having the following contents, in percent by mass: guanidine nitrate at about 48%; basic copper nitrate at about 42%; strontium nitrate at about 2.5%; ammonium perchlorate at about 3%; strontium zirconate at about 1.5%; zirconium silicate at about 2.5%; talc at about 0.5%.

[0152] These components were weighed and then were pressed into round tablets with a diameter of 5 mm and a thickness of 1.9 mm by wet granulation and by a rotary tablet press. The specific preparation method was carried out as follows. Guanidine nitrate, basic copper nitrate, strontium nitrate, ammonium perchlorate, strontium zirconate, zirconium silicate, and talc were mixed by a mixing device to obtain a first material; 10% of distilled water was added to the first material and the first material was subjected to wet kneading for 60 min to obtain a second material, and the second material was caused to pass through a 40-mesh sieve to obtain a third material; the third material was dried to a water content less than 0.5% of the total mass of the third material and was caused to pass through the 40-mesh sieve again to obtain a fourth material; talc was added to the fourth material, and the material was molded by a rotary tablet press.

[0153] The prepared round tablets were loaded into a test generator and subjected to an ignition and combustion test. After the test, the generator was dissected to observe the form of the combusted tablets.

[0154] FIG. 9 was a picture showing the morphology of residues obtained after combustion of the gas generant composition tablets in Example 6 of the present disclosure. Table 9 below showed statistics of the weights of soluble residues and insoluble residues discharged after the combustion of the gas generant composition tablets in Example 6 of the present disclosure and their low-temperature ignition delay time. It could be seen from FIG. 9 and Table 9 that after combusted at high temperature, the tablets were in the form of the original tablet and exhibited a significant coagulation effect. The residues were tightly attached to the inner wall of the filter and had larger density. The tablets had retained a very good original appearance and had higher strength and higher density to support the maintaining of their original appearance. Their low-temperature ignition time met the requirement of being less than 7 ms.

TABLE-US-00009 TABLE 9 Water-soluble Insoluble Total Ignition PH Matter Matter Weight Delay No. Value Weight (g) Weight (g) (g) Time (ms) 1 5.68 0.299 0.012 0.311 2.9 2 5.49 0.367 0.091 0.458 3.0 3 5.87 0.354 0.059 0.413 2.8 AVE 5.68 0.340 0.054 0.394 2.9

[0155] In this example, strontium zirconate and zirconium silicate were added as a slag-forming agent, basic copper nitrate was used as a primary oxidizer, guanidine nitrate was used as a fuel, AP and strontium nitrate were used as auxiliary oxidizers, and talc was used as a lubricant and a release agent. The tablets retained a very good original appearance after being tested in a generator for an airbag. After a TANKWASH test was conducted, the weight of the water-soluble matter and the weight of the insoluble matter were decreased significantly. Moreover, the composition was combusted at an increased speed and had an ignition delay that met the strict requirements of USCAR.

[0156] In each of the above-mentioned Comparative Examples and Examples of the present disclosure, three parallel tests were conducted and an average value was obtained therefrom.

[0157] The present disclosure further provides a gas generant composition, comprising guanidine nitrate, basic copper nitrate and ammonium perchlorate and characterized by further comprising a slag-forming agent and a lubricant, wherein the slag-forming agent (slagging agent) is at least one zirconate, or at least one silicate, or a mixture of at least one zirconate and at least one silicate.

[0158] The contents, in percent by mass, of the respective components are as follows: guanidine nitrate at about 40% to 60%; basic copper nitrate at about 25% to 50%; ammonium perchlorate at about 0% to 7%; slag-forming agent at about 1% to 10%; and lubricant at about 0.05% to 5%.

[0159] In the gas generant composition described above, mass percentage of the guanidine nitrate may be, but is not limited to, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59% and 60%.

[0160] In the gas generant composition described above, mass percentage of the basic copper nitrate may be, but is not limited to, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49% and 50%.

[0161] In the gas generant composition described above, mass percentage of the ammonium perchlorate may be, but is not limited to, 0%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6% and 7%.

[0162] In the gas generant composition described above, mass percentage of the slag-forming agent may be, but is not limited to, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% and 10%.

[0163] In the gas generant composition described above, mass percentage of the lubricant may be, but is not limited to, 0.05%, 0.5%, 1%, 2%, 3%, 4% and 5%.

[0164] In the gas generant composition described above, the zirconate is one or a combination of strontium zirconate, barium zirconate, or calcium zirconate.

[0165] In the gas generant composition described above, the zirconate is barium zirconate.

[0166] In the gas generant composition described above, the silicate is one or a combination of zirconium silicate or calcium silicate.

[0167] In the gas generant composition described above, the slag-forming agent is a mixture of at least one zirconate and at least one silicate, in which the mass ratio of zirconate to silicate is 1:0.5-3, preferably 1:0.8-2.

[0168] In the gas generant composition described above, the slag-forming agent is a mixture of strontium zirconate, zirconium silicate, and calcium silicate in a mass ratio of 1:0.2-1.5:0.3-1.5, preferably 1:0.3-1:0.5-1.

[0169] In the gas generant composition described above, the slag-forming agent is a mixture of strontium zirconate and barium zirconate in a mass ratio of 1:0.5-3, preferably 1:0.8-2.

[0170] In the gas generant composition described above, the lubricant is one or a combination of talc, graphite, calcium stearate, magnesium stearate, molybdenum disulfide, or boron nitride.

[0171] In the gas generant composition described above, the ammonium perchlorate has a particle size D90 not greater than 20 μm; and the slag-forming agent has a particle size D90 not greater than 5 μm.

[0172] In the gas generant composition described above, the basic copper nitrate and the lubricant each have a particle size D90 not greater than 5 μm.

[0173] In the gas generant composition described above, the basic copper nitrate has a specific surface area of 1.0-8.0 m.sup.2/g, preferably 2.0-6.0 m.sup.2/g.

[0174] In the gas generant composition described above, a sum of water contents in the respective components of the gas generant composition is not more than 1% of the total mass of the respective components.

[0175] In the gas generant composition described above, the gas generant composition is molded as a circular or elliptical sheet structure, a circular or elliptical columnar structure, a special-shaped sheet or columnar structure, a circular or elliptical monoporous structure, a circular or elliptical porous structure, or a special-shaped monoporous or porous structure.

[0176] In the gas generant composition described above, the circular sheet structure has a diameter of 3 to 15 mm and a height of 2 to 5 mm; the circular columnar structure has a diameter of 3 to 15 mm and a height of 5 to 15 mm; the circular monoporous structure has an inner diameter of 0.5 to 2.5 mm, an outer diameter of 3 to 15 mm, and a height of 3 to 15 mm; and the elliptical monoporous structure has an inner diameter of 0.5 to 2.5 mm, a major diameter of 3 to 20 mm, a minor diameter of 2 to 12 mm, and a height of 3 to 15 mm.

[0177] A method for preparing a gas generant composition according to the present disclosure may be carried out by a method comprising wet granulation, spray granulation, or dry granulation. Here, spray granulation or dry granulation may be carried out by using a traditional granulation process method.

[0178] Here, a specific preparation method for wet granulation includes the following steps.

[0179] (1) Guanidine nitrate, basic copper nitrate, ammonium perchlorate, and a slag-forming agent are mixed to obtain a first material, where they are mixed in a mixing device for a mixing duration larger than or equal to 5 min. The mixing device may be a pneumatic mixer, a V-type mixer, a three-dimensional multi-directional motion mixer, an automatic lifting hopper mixer, a vibration mill, a ribbon mixer, or an acoustic resonance mixer.

[0180] (2) The first material is subjected to wet mixing with addition of water to obtain a second material, where the wet mixing is performed for a duration of 20 min to 60 min, wherein the amount of water added is 5% to 15% of the total mass of the first material, and distilled water is preferably added. The device for wet mixing is a kneader or a mixer and may, for example, be selected from a horizontal kneader, a vertical kneader, a ribbon mixer, or an acoustic resonance mixer.

[0181] (3) The second material is caused to pass through a sieve having 10 to 40 meshes to obtain a third material.

[0182] (4) The third material is dried to a water content less than 0.5% of the total mass of the third material and is caused to pass through the sieve (screen) having 10 to 40 meshes again to obtain a fourth material. The drying device may be an electric heating oven, an oil bath oven, a steam oven, a double-cone oven, a vibrating fluidized bed, or a belt vacuum dryer.

[0183] (5) A lubricant is added to the fourth material and the material is molded. The molding device may be a hydraulic press, a rotary tablet press, or a powder molding machine. It may be molded as a circular or elliptical sheet structure, a circular or elliptical columnar structure, a special-shaped sheet or columnar structure, a circular or elliptical monoporous structure, a circular or elliptical porous structure, or a special-shaped monoporous or porous structure. In an optional embodiment of the present disclosure, the circular sheet structure has a diameter of 3 to 15 mm and a height of 2 to 5 mm; the circular columnar structure has a diameter of 3 to 15 mm and a height of 5 to 15 mm; the circular monoporous structure has an inner diameter of 0.5 to 2.5 mm, an outer diameter of 3 to 15 mm, and a height of 3 to 15 mm; and the elliptical monoporous structure has an inner diameter of 0.5 to 2.5 mm, a major diameter of 3 to 20 mm, a minor diameter of 2 to 12 mm, and a height of 3 to 15 mm.

[0184] Another specific preparation method for wet granulation includes the following steps.

[0185] (1) Guanidine nitrate, basic copper nitrate, ammonium perchlorate, a slag-forming agent, and a lubricant are mixed to obtain a first material, where they are mixed in a mixing device for a mixing duration larger than or equal to 5 min. The mixing device may be a V-type mixer, a three-dimensional multi-directional motion mixer, an automatic lifting hopper mixer, a vibration mill, a ribbon mixer, or an acoustic resonance mixer.

[0186] (2) The first material is subjected to wet mixing with addition of water to obtain a second material, where the wet mixing is performed for a duration of 20 min to 60 min, wherein the amount of water added is 5% to 15% of the total mass of the first material, and distilled water is preferably added. The device for wet mixing is a kneader or a mixer and may, for example, be selected from a horizontal kneader, a vertical kneader, a ribbon mixer, or an acoustic resonance mixer.

[0187] (3) The second material is caused to pass through a sieve having 10 to 40 meshes to obtain a third material.

[0188] (4) The third material is dried to a water content less than 0.5% of the total mass of the third material and is caused to pass through the sieve having 10 to 40 meshes again to obtain a fourth material. The drying device may be an electric heating oven, an oil bath oven, a steam oven, a double-cone oven, a vibrating fluidized bed, or a belt vacuum dryer.

[0189] (5) The fourth material is molded. The molding device may be a hydraulic press, a rotary tablet press, or a powder molding machine.

[0190] The above-mentioned gas generant composition of the present disclosure is used in a gas generator of a vehicle airbag.

[0191] In the following examples, the mixing device used is a three-dimensional multi-directional motion mixer (or an ultra-efficient mixer), the kneader used is a horizontal kneader, the drying device used is a vacuum oven, and the molding device used is a rotary tablet press.

[0192] The study found that when gas generant compositions of different formulation ratios are burned, as the oxygen balance of the gas generant composition formulation decreases, the contents of CO, NO, NH.sub.3 and HCl show an increase trend, while the contents of NO.sub.2 and Cl.sub.2 show a decrease trend; and when the oxygen balance of the gas generant composition formulation increases, the opposite trend will appear, that is, the contents of CO, NO, NH.sub.3 and HCl will show a decrease trend, while the contents of NO.sub.2 and Cl.sub.2 will show an increase trend.

[0193] Therefore, if the oxygen balance of the gas generant composition formulation is too high or too low, the content of at least a part of the toxic and harmful gases generated when the gas generant composition is burned will exceed the limit content specified in the USCAR, thereby failing to meet the regulations of standard USCAR and AK-LV, and cause harm to the user's body, and cause pollution to the environment.

[0194] After a lot of research, the inventor found that when the oxygen balance of the gas generant composition formulation is 0 to −3, the contents of the toxic and harmful gases (including NO.sub.x, Cl.sub.2, HCl, CO, NH.sub.3, etc.) generated when the gas generating agent is burned can meets the limit requirements of the standard USCAR and AK-LV for the contents of toxic and harmful gases.

[0195] Therefore, in order to achieve the above oxygen balance, the inventor further optimizes the formulation of the gas generant composition. Specifically, on the basis of the foregoing formulation, strontium nitrate as an auxiliary oxidizer is discarded, and the ratios of the remaining components are optimized.

[0196] A detailed description will be given below based on specific embodiments.

Example I

[0197] A gas generant composition comprised components having the following contents, in percent by mass: guanidine nitrate 52.0%, basic copper nitrate 42.0%, ammonium perchlorate 2%, barium zirconate 3%, calcium stearate 1%.

[0198] These components were weighed and then were pressed into round tablets with a diameter of 5 mm and a thickness of 1.9 mm by wet granulation and by a rotary tablet press. The specific preparation method was carried out as follows. Guanidine nitrate, basic copper nitrate, ammonium perchlorate, and barium zirconate were mixed by a mixing device to obtain a first material; 15% of distilled water was added to the first material and the first material was subjected to wet kneading for 60 min to obtain a second material, and the second material was caused to pass through a 40-mesh sieve to obtain a third material; the third material was dried to a water content less than 0.5% of the total mass of the third material and was caused to pass through the 40-mesh sieve again to obtain a fourth material; and calcium stearate was added to the fourth material, and the material was molded by a rotary tablet press.

[0199] The oxygen balance of the gas generant composition formulation in this example is −0.353.

Example II

[0200] A gas generant composition comprised components having the following contents, in percent by mass: guanidine nitrate 52.0%, basic copper nitrate 41.0%, ammonium perchlorate 2%, barium zirconate 4%, calcium stearate 1%.

[0201] These components were weighed and then were pressed into round tablets with a diameter of 5 mm and a thickness of 1.9 mm by wet granulation and by a rotary tablet press. The specific preparation method was carried out as follows. Guanidine nitrate, basic copper nitrate, ammonium perchlorate, barium zirconate, and calcium stearate were mixed by a mixing device to obtain a first material; 10% of distilled water was added to the first material and the first material was subjected to wet kneading for 50 min to obtain a second material, and the second material was caused to pass through a 35-mesh sieve to obtain a third material; the third material was dried to a water content less than 0.5% of the total mass of the third material and was caused to pass through the 35-mesh sieve again to obtain a fourth material; calcium stearate was added to the fourth material, and the material was molded by a rotary tablet press.

[0202] The oxygen balance of the gas generant composition formulation in this example is −0.653.

Comparative Example I

[0203] A gas generant composition comprised components having the following contents, in percent by mass: guanidine nitrate 51.0%, basic copper nitrate 41.5%, strontium nitrate 2.5%, ammonium perchlorate 2%, strontium titanate 2%, talc 1%.

[0204] These components were weighed and then were pressed into round tablets with a diameter of 5 mm and a thickness of 1.9 mm by wet granulation and by a rotary tablet press. The specific preparation method was carried out as follows. Guanidine nitrate, basic copper nitrate, strontium nitrate, ammonium perchlorate, and barium zirconate were mixed by a mixing device to obtain a first material; 15% of distilled water was added to the first material and the first material was subjected to wet kneading for 60 min to obtain a second material, and the second material was caused to pass through a 40-mesh sieve to obtain a third material; the third material was dried to a water content less than 0.5% of the total mass of the third material and was caused to pass through the 40-mesh sieve again to obtain a fourth material; talc was added to the fourth material, and the material was molded by a rotary tablet press.

[0205] The oxygen balance of the gas generant composition formulation in this example is 0.704.

Experimental Example I

[0206] The prepared gas generant composition round tablets were loaded into the test generator, and the ignition and combustion test was performed, and the Fourier infrared gas analyzer was used to measure the ingredients and contents of the generated gas after combustion, which were compared with the relevant data in USCAR. See Table 10 for specific ingredients and contents and comparison results.

TABLE-US-00010 TABLE 10 Comparison table of gas ingredients and contents (unit: ppm) No. CO NO.sub.2 NO NH.sub.3 Cl.sub.2 HCl USCAR Limits 115 1.3 18.8 12.5 0.25 1.3 Example I 84.5 0.69 10.1 5.53 0.12 0.33 Example II 94.8 1.13 12.36 9.98 0.15 0.17 Comparative Example I 36 11.9 28.2 0.06 0.16 0.16

[0207] It can be seen from the above experimental results that although in the gases generated after combustion in Comparative Example I containing strontium nitrate, contents of some gases are lower than those in the examples (such as CO and NH.sub.3), the contents of nitrides rise sharply and are much higher than the contents specified in USCAR. The content of each toxic and harmful gas generated by the gas generant composition prepared in Examples I-II after combustion is far lower than the limit content given in USCAR and thus meets the standards of USCAR.

[0208] Furthermore, the inventor also found that by experimenting with different slagging agents, under the condition that the other components and contents of the formulation remain unchanged, the morphology of the residues after the generator detonation is different, and the concentration of the suspended matter in the air after the combustion of the gas generating agent is also different.

[0209] Therefore, screening the slagging agent to determine the most suitable slagging agent can keep the morphology of the residues after combustion of the prepared gas generant composition to be relatively complete; and the concentration of the resulting suspended matter in the air is far lower than the limit concentration given in USCAR, which satisfies the USCAR standards.

[0210] A detailed description will be given below based on specific embodiments.

Example III

[0211] A gas generant composition comprised components having the following contents, in percent by mass: guanidine nitrate 48.0%, basic copper nitrate 43.5%, ammonium perchlorate 2.5%, strontium titanate 3%, talc 3%.

[0212] These components were weighed and then were pressed into round tablets with a diameter of 5 mm and a thickness of 1.9 mm by wet granulation and by a rotary tablet press. The specific preparation method was carried out as follows. Guanidine nitrate, basic copper nitrate, ammonium perchlorate, strontium titanate, and talc were mixed by a mixing device to obtain a first material; 10% of distilled water was added to the first material and the first material was subjected to wet kneading for 50 min to obtain a second material, and the second material was caused to pass through a 30-mesh sieve to obtain a third material; the third material was dried to a water content less than 0.5% of the total mass of the third material and was caused to pass through the 30-mesh sieve again to obtain a fourth material; talc was added to the fourth material, and the material was molded by a rotary tablet press.

Example IV

[0213] In this example, except for replacing the strontium titanate with barium zirconate, the content of the rest of the formulation remains unchanged.

Experimental Example II

[0214] The prepared gas generant composition round tablets were loaded into the test generator, and the ignition and combustion test was performed to measure the total suspended particulates generated after combustion, which will be compared with the relevant data in USCAR. See Table 11 for specific contents and comparison results.

TABLE-US-00011 TABLE 11 Comparison of total suspended particulates total water suspended insoluble slagging particulates, matter, water soluble No. agent mg/3 mg/3 matter, mg/3 USCAR Limits 83.33 33 50 Example III strontium 125.11 36.9 87.7 titanate Example IV barium 22.5 4.2 18.3 zirconate

[0215] The prepared round tablets were put into the test generator and the ignition and combustion tests were carried out. After the test, the generator was dissected and the morphology of the tablets after burning was observed.

[0216] FIGS. 10 and 11 respectively show the morphology of the residues after combustion of the gas generant composition round tablets in Example III and Example IV (that is, the slagging agent is strontium titanate and barium zirconate, respectively).

[0217] It can be seen from FIG. 11 that compared to the morphology of the residue shown in FIG. 10, the gas generant composition round tablets with barium zirconate as the slagging agent are in the form of the original tablet after being burned at high temperature, which has a significant coagulation effect, and the residue tightly adheres to the inner wall of the filter screen, its density is relatively high, the tablet maintains its original shape very well, and has a harder strength and higher density to support it to maintain its original morphology.

[0218] In summary, by replacing and screening suitable slagging agents, the morphology of the residues after the generator is detonated can be effectively maintained, and the concentration of suspended matter in the air after the combustion of the gas generating agent can be reduced.

[0219] The above description is merely illustrative of the most preferable specific embodiments of the present disclosure, but the claimed scope of the present disclosure is not limited thereto. Any variations or alternatives that can readily envisaged by those skilled in the art within the technical scope disclosed in the present disclosure are intended to be encompassed within the claimed scope of the present disclosure.

[0220] Matters that are not described in detail in the specification of the present disclosure are technically well known to those skilled in the art.